From: Ming Lei <ming.lei@redhat.com>
To: James Smart <james.smart@broadcom.com>
Cc: Sagi Grimberg <sagi@grimberg.me>, Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Keith Busch <kbusch@kernel.org>,
linux-nvme@lists.infradead.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH RFC 0/3] blk-mq/nvme: use blk_mq_alloc_request() for NVMe's connect request
Date: Wed, 20 Nov 2019 14:35:50 +0800 [thread overview]
Message-ID: <20191120063550.GA3664@ming.t460p> (raw)
In-Reply-To: <fda43a50-a484-dde7-84a1-94ccf9346bdd@broadcom.com>
On Tue, Nov 19, 2019 at 09:56:45AM -0800, James Smart wrote:
> On 11/18/2019 4:05 PM, Sagi Grimberg wrote:
> >
> > This is a much simpler fix that does not create this churn local to
> > every driver. Also, I don't like the assumptions about tag reservations
> > that the drivers is taking locally (that the connect will have tag 0
> > for example). All this makes this look like a hack.
>
> Agree with Sagi on this last statement. When I reviewed the patch, it was
> very non-intuitive. Why dependency on tag 0, why a queue number squirrelled
> away on this one request only. Why change the initialization (queue pointer)
> on this one specific request from its hctx and so on. For someone without
> the history, ugly.
>
> >
> > I'm starting to think we maybe need to get the connect out of the block
> > layer execution if its such a big problem... Its a real shame if that is
> > the case...
>
> Yep. This is starting to be another case of perhaps I should be changing
> nvme-fc's blk-mq hctx to nvme queue relationship in a different manner. I'm
> having a very hard time with all the queue resources today's policy is
> wasting on targets.
Wrt. the above two points, I believe both are not an issue at all by
this driver specific approach, see my comment:
https://lore.kernel.org/linux-block/fda43a50-a484-dde7-84a1-94ccf9346bdd@broadcom.com/T/#mb72afa6ed93bc852ca266779977634cf6214b329
Thanks,
Ming
WARNING: multiple messages have this Message-ID (diff)
From: Ming Lei <ming.lei@redhat.com>
To: James Smart <james.smart@broadcom.com>
Cc: Jens Axboe <axboe@kernel.dk>, Sagi Grimberg <sagi@grimberg.me>,
linux-nvme@lists.infradead.org, linux-block@vger.kernel.org,
Keith Busch <kbusch@kernel.org>, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH RFC 0/3] blk-mq/nvme: use blk_mq_alloc_request() for NVMe's connect request
Date: Wed, 20 Nov 2019 14:35:50 +0800 [thread overview]
Message-ID: <20191120063550.GA3664@ming.t460p> (raw)
In-Reply-To: <fda43a50-a484-dde7-84a1-94ccf9346bdd@broadcom.com>
On Tue, Nov 19, 2019 at 09:56:45AM -0800, James Smart wrote:
> On 11/18/2019 4:05 PM, Sagi Grimberg wrote:
> >
> > This is a much simpler fix that does not create this churn local to
> > every driver. Also, I don't like the assumptions about tag reservations
> > that the drivers is taking locally (that the connect will have tag 0
> > for example). All this makes this look like a hack.
>
> Agree with Sagi on this last statement. When I reviewed the patch, it was
> very non-intuitive. Why dependency on tag 0, why a queue number squirrelled
> away on this one request only. Why change the initialization (queue pointer)
> on this one specific request from its hctx and so on. For someone without
> the history, ugly.
>
> >
> > I'm starting to think we maybe need to get the connect out of the block
> > layer execution if its such a big problem... Its a real shame if that is
> > the case...
>
> Yep. This is starting to be another case of perhaps I should be changing
> nvme-fc's blk-mq hctx to nvme queue relationship in a different manner. I'm
> having a very hard time with all the queue resources today's policy is
> wasting on targets.
Wrt. the above two points, I believe both are not an issue at all by
this driver specific approach, see my comment:
https://lore.kernel.org/linux-block/fda43a50-a484-dde7-84a1-94ccf9346bdd@broadcom.com/T/#mb72afa6ed93bc852ca266779977634cf6214b329
Thanks,
Ming
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next prev parent reply other threads:[~2019-11-20 6:36 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-15 10:42 [PATCH RFC 0/3] blk-mq/nvme: use blk_mq_alloc_request() for NVMe's connect request Ming Lei
2019-11-15 10:42 ` Ming Lei
2019-11-15 10:42 ` [PATCH RFC 1/3] block: reuse one scheduler/flush field for private request's data Ming Lei
2019-11-15 10:42 ` Ming Lei
2019-11-15 10:42 ` [PATCH RFC 2/3] nvme: don't use blk_mq_alloc_request_hctx() for allocating connect request Ming Lei
2019-11-15 10:42 ` Ming Lei
2019-11-15 10:42 ` [PATCH RFC 3/3] blk-mq: kill blk_mq_alloc_request_hctx() Ming Lei
2019-11-15 10:42 ` Ming Lei
2019-11-15 22:38 ` [PATCH RFC 0/3] blk-mq/nvme: use blk_mq_alloc_request() for NVMe's connect request Sagi Grimberg
2019-11-15 22:38 ` Sagi Grimberg
2019-11-16 7:17 ` Ming Lei
2019-11-16 7:17 ` Ming Lei
2019-11-17 1:24 ` Bart Van Assche
2019-11-17 1:24 ` Bart Van Assche
2019-11-17 4:12 ` Ming Lei
2019-11-17 4:12 ` Ming Lei
2019-11-18 23:27 ` Bart Van Assche
2019-11-18 23:27 ` Bart Van Assche
2019-11-19 0:05 ` Sagi Grimberg
2019-11-19 0:05 ` Sagi Grimberg
2019-11-19 0:34 ` Keith Busch
2019-11-19 0:34 ` Keith Busch
2019-11-19 1:43 ` Sagi Grimberg
2019-11-19 1:43 ` Sagi Grimberg
2019-11-19 2:38 ` Ming Lei
2019-11-19 2:38 ` Ming Lei
2019-11-19 2:33 ` Ming Lei
2019-11-19 2:33 ` Ming Lei
2019-11-19 17:56 ` James Smart
2019-11-19 17:56 ` James Smart
2019-11-20 6:35 ` Ming Lei [this message]
2019-11-20 6:35 ` Ming Lei
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